Labels

Thursday, 18 February 2016

NATURAL VEGETATION

NATURAL VEGETATION

• It refers to a plant community which has grown naturally without human
aid and has been left undisturbed by humans for a long time termed
as a virgin vegetation.
• cultivated crops and fruits, orchards form part of vegetation but not
natural vegetation.
• The virgin vegetation, which are purely Indian are known as endemic
or indigenous species but those which have come from outside India are termed as
exotic plants.
• The term flora is used to denote plants of a particular region or period.
• the species of animals are referred to as fauna.
• The sandy soils of the desert support cactus and thorny bushes while wet,
marshy, deltaic soils support mangroves and deltaic vegetation.

•
Why are the southern slopes in Himalayan region covered with thick vegetation
cover as compared to northern slopes of the same hills?
• Answer-The growth of vegetation depends upon the amount of sunlight and
rainfall received.

• The southern slopes of
the Himalaya receives more rain due to south west monsoon winds which travel
west along the southern slops.

•The northern slopes do not
receive any such rainfall.
• All the plants and animals in an area are interdependent and interrelated to
each other in their physical environment forming an ecosystem.

•
restricted to heavy rainfall
• best in areas having more than 200 cm of
rainfall with a short dry season.
• trees reach great heights up to 60 metres or even above.
• region is warmand wet throughout the year.

• It has a luxuriant
vegetation of all kinds – trees, shrubs, and creepers giving it a multilayered
structure.
• no definite time for trees to shed their leaves.
• appear green all the year round.

•Some of the commercially
important trees of this forest are ebony, mahogany, rosewood,
rubber and cinchona.• common animals found in these forests are elephants,
monkey, lemur and deer.• The one horned rhinoceros are found in the jungles
of Assam and West Bengal.
• Besides these animals plenty of birds, bats, sloth, scorpions and snails are
also found in these jungles.

Tropical Deciduous Forests:

•
most widespread forests of India.
• also called the monsoon forests and spread over the region receiving
rainfall between 200 cm and 70 cm.
• Trees of this forest-type shed their leaves
for about six to eight weeks in dry summer.
• On the basis of the availability of water, these forests are further divided
into moist and dry deciduous.

moist deciduous:

•
It found in areas receiving rainfall between 200 and 100 cm.
• Exist mostly in the eastern part of the country – northeastern states,
along the foothills of the Himalayas, Jharkhand, W est Orissa
and Chhattisgarh, and on the eastern slopes of the Western Ghats.
• Teak is the most dominant species of this forest.
Bamboos, sal, shisham, sandalwood, khair , kusum, arjun, mulberry are other
commercially important species.

dry deciduous:

• The
dry deciduous forests are found in areas having rainfall between 100 cm
and 70cm.
• These forests are found in the rainier parts of the peninsular
plateau and the plains of Bihar and Uttar Pradesh.
• There are open stretches in which Teak, Sal, Peepal, and Neemgrow.
• A large part of this region has been cleared for cultivation and some parts
are used for grazing.
• common animals found are lion, tiger , pig, deer and elephant.
• variety of birds, lizards, snakes, and tortoises are also found here.

The Thorn Forests and Scrubs :

•
In regions with less than 70 cm of rainfall, the natural vegetation
consists of thorny trees and bushes.
• found in the north-western part of the country including semi-arid
areas of Gujarat, Rajasthan, Madhya Pradesh, Chhattisgarh, Uttar Pradesh and
Haryana.
• Acacias, palms, euphorbias and cacti are the main plant
species.
• Trees are scattered and have long roots penetrating deep into the soil in order to get moisture.
• The stems are succulent to conserve water.
• Leaves are mostly thick and small to minimize evaporation.
• give way to thorn forests and scrubs in arid areas.
• common animals are rats, mice, rabbits, fox, wolf, tiger, lion, wild ass, horses and
camels.

Montane Forests :

•
In mountainous areas, the decrease in temperature with increasing altitude leads to the
corresponding change in natural vegetation.
• As such, there is a succession of natural vegetation belts in the same order
as we see from the tropical to the tundra region.
• The wet temperate type of forests are found between a height
of 1000 and 2000 metres.• Evergreen broad-leaf trees such as oaks
and chestnuts predominate.
• Between 1500 and 3000 metres, temperate forests containing
coniferous trees like pine, deodar, silver fir, spruce and cedar,
are found.
• cover mostly the southern slopes of the Himalayas, places having high
altitude in southern and north-east India.
• At higher elevations, temperate grasslands are common.
• At high altitudes, generally more than 3,600 metres
above sea-level, temperate forests and grasslands give way to the Alpine
vegetation.
• Silver fir, junipers, pines and birches
are the common trees of these forests.
• get progressively stunted as they approach the snow-line.
• used extensively for grazing by nomadic tribes like the Gujjars and the
Bakarwals.
• At higher altitudes, mosses and lichens form part of tundra vegetation.
• common animals found in these forests are Kashmir stag, spotted dear , wild
sheep, jack rabbit, Tibetan antelope, yak, snow leopard, squirrels, Shaggy horn
wild ibex, bear and rare red panda, sheep and goats with thick hair.

Mangrove Forests

•
found in the areas of coasts influenced by tides.
• Mud and silt get accumulated on such coasts.
• Dense mangroves are the common varieties with roots of the plants submerged
under water .
• The deltas of the Ganga, the Mahanadi, the Krishana, the Godavari and the Kaveri are covered by such vegetation.
• In the Ganga Brahamaputra delta, sundari trees are found, which provide
durable hard timber.
• Palm, coconut, keora, agar, also grow in some parts of the delta.
• Royal Bengal Tiger is the famous animal in these forests.• Turtles, crocodiles, gharials and snakes
are also found in these forests.